<template>
  <div class="home-page">
    <div class="banner">
      <div class="container">
        <h1 class="logo-font">conduit</h1>
        <p>A place to share your knowledge.</p>
      </div>
    </div>

    <div class="container page">
      <div class="row">
        <div class="col-md-9">
          <div class="feed-toggle">
            <ul class="nav nav-pills outline-active">
              <li v-if="user" class="nav-item" :class="{active: tab === 'your_feed'}">
                <nuxt-link
                  class="nav-link"
                  :to="{
                    name: 'home',
                    query: {
                      tab: 'your_feed'
                    }
                  }"
                  exact
                >Your Feed</nuxt-link>
              </li>
              <li class="nav-item" :class="{active: tab === 'global_feed'}">
                <nuxt-link
                  class="nav-link"
                  :to="{
                    name: 'home'
                  }"
                  exact
                >Global Feed</nuxt-link>
              </li>
              <li v-if="tag" class="nav-item" :class="{active: tab === 'tag'}">
                <nuxt-link
                  class="nav-link"
                  :to="{
                    name: 'home',
                    query: {
                      tab: 'tag',
                      tag: tag
                    }
                  }"
                  exact
                > # {{ tag }} </nuxt-link>
              </li>
            </ul>
          </div>

          <div
            class="article-preview"
            v-for="article in articles"
            :key="article.slug"
          >
            <div class="article-meta">
              <nuxt-link
                :to="{
                  name: 'profile',
                  params: {
                    username: article.author.username
                  }
                }"
                ><img :src="article.author.image"
              /></nuxt-link>
              <div class="info">
                <nuxt-link
                  :to="{
                    name: 'profile',
                    params: {
                      username: article.author.username
                    }
                  }"
                  class="author"
                >{{article.author.username}}</nuxt-link>
                <span class="date">{{article.createdAt | date('MMM DD, YYYY')}}</span>
              </div>
              <button
                class="btn btn-outline-primary btn-sm pull-xs-right"
                :class="{active: article.favorited}"
                @click="onFavorite(article)"
                :disabled="article.favoriteDisabled"
              >
                <i class="ion-heart"></i> {{article.favoritesCount}}
              </button>
            </div>
            <nuxt-link :to="{
              name: 'article',
              params: {
                slug: article.slug
              }
            }" class="preview-link">
              <h1>{{article.title}}</h1>
              <p>{{article.description}}</p>
              <span>Read more...</span>
            </nuxt-link>
          </div>

          <!-- 分页 -->
          <nav>
            <ul class="pagination">
              <li class="page-item" :class="{active: item === page}" v-for="item in totalPage" :key="item">
                <nuxt-link class="page-link" :to="{
                  name: 'home',
                  query: {
                    page: item,
                    tag: $route.query.tag,
                    tab
                  }
                }">{{item}}</nuxt-link>
              </li>
            </ul>
          </nav>
        </div>

        <div class="col-md-3">
          <div class="sidebar">
            <p>Popular Tags</p>

            <div class="tag-list">
              <nuxt-link
                :to="{
                  name: 'home',
                  query: {
                    tag: item,
                    tab: 'tag'
                  }
                }"
                class="tag-pill tag-default"
                v-for="item in tags"
                :key="item"
              >{{item}}</nuxt-link>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</template>

<script>
import { getArticles, getYourFeedArticles, addFavorite, deleteFavorite } from '@/api/article'
import { getTags } from '@/api/tag'
import { mapState } from 'vuex'
export default {
  name: "HomePage",
  watchQuery: ['page', 'tag', 'tab'],
  async asyncData ({ query }) {
    const page = Number.parseInt(query.page || 1)
    const limit = 20
    const tab = query.tab || 'global_feed'
    const tag = query.tag
    const loadArticles = tab !== 'your_feed'
    ? getArticles
    : getYourFeedArticles
    const [articleRes, tagRes] = await Promise.all([
      loadArticles({
        limit,
        offset: (page - 1) * limit,
        tag: query.tag
      }),
      getTags()
    ])
    const { articles, articlesCount } = articleRes.data
    const { tags } = tagRes.data

    articles.forEach(article => article.favoriteDisabled = false)

    return {
      limit,
      page,
      articles,
      articlesCount,
      tags,
      tab,
      tag
    }
  },
  computed: {
    totalPage () {
      return Math.ceil(this.articlesCount / this.limit)
    },
    ...mapState(['user'])
  },
  methods: {
    async onFavorite (article) {
      if (!this.user ) return this.$router.push('/login')
      article.favoriteDisabled = true // 禁用点击
      if(article.favorited) {
        // 取消点赞
        await deleteFavorite(article.slug)
        article.favorited = false
        article.favoritesCount -= 1
      } else {
        // 添加点赞
        await addFavorite(article.slug)
        article.favorited = true
        article.favoritesCount += 1
      }
      article.favoriteDisabled = false // 允许点击
    }
  }
};
</script>
